I would like to make a 10' x 16' shed using concrete blocks for the base. Should I put sand or cement under the blocks?
How to make a good base for a shed
shed
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Personally, I would dig the topsoil out from under the blocks—preferably down to mineral soil so that almost all of the concrete is buried. This makes less of a step up for wheeled equipment and less space for critters and weeds to grow underneath. I put mine very close to the ground on concrete blocks with slots for 2 inch wide lumber and concrete screws through the joist into the block to keep the wind from lifting it up:
The kind of concrete block you are using is plenty strong, though I don't see anything to keep your shed from moving, for example from strong wind, heavy rain, or leaning livestock.
The strength of the joists is the next weakest link in this design. Some more support in the middle could be overkill, but it is unlikely to be so.
I think:
No, it is not a good idea. You can expect all the difficulties of renovation, new construction, and building relocation, combined. Perhaps also conflicts with land use regulations as well. Without tying the roof to the adjacent structure, expect water damage to both the shed and the home.
Support for the shed should be suitable for the soil and drainage conditions local to the site. A proper foundation would be the preferred solution. Whatever is constructed should be in accord with current building codes and meet the requirements for wind and seismic forces.
A concrete slab might provide better long term performance.
See answer 3.
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Best Answer
Get Local Building Dept. approval, they'll direct you on this as well. But, 4" of tamped sand only works if it's retained, it washes away. Tamped 3/4" jagged gravel at 4" deep is the best choice. The bigger issue is tying the building down from wind loft. This is where a concrete filled cinderblock & poured concrete foundation may be required. Don't mess with the Town, they'll fine you $1000's & also make you tear it down regardless of how right it's built.